Commutator-cylinder for dynamo-electric machines.



R. E. HELLMUND.

COMMUTATOR CYLINDER FOR DYNAMO ELECTRIC MACHINES. APPLICATION FILEDSEPT-27,1916.

1,293,770. Patented Feb. 11, 1919 UNITED STATES PATENT OFFICE.

RUDOLF E. HELLMUND, 0F SWISSVALE, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-SYLVANIA.

Specification of Letters Patent.

Patented Feb. 11, 1919.

Application filed September 27, 1916. Serial No. 122,374.

To all whom it may concern Be it known that I, RUDoLF E. HELLMUND, asubject of the Emperor of Germany, and a resident of Swissvale, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in commutator Cylinders for Dynamo Electric Machines,of which the following is a specification. v Y

My invention relates to the construction of commutator cylinders fordynamo-electric machines, and it has for its object to provide acommutator cylinder that is particularly adapted for use in connectionwith dynamo-electric machines of the high-voltage type.

In the construction of commutator cylinders for high voltage, it isessential that suficient insulation be provided in order to preventelectrical discharges between the conducting segments which are atmachine potential and the V rings which are at ground potential. Theobvious expedient is to increase the length of the creepage path whichis usually defined as the shortest distance over the exposed surfaces ofthe insulating material between the live parts and the ground. Thedesired results have heretofore been obtained by merely extending theinsulation beyond the conducting segments, but, owing to the spacelimitations existing in certain types of apparatus, such as railwaymotors, this has not always been found practicable.

According to the present invention, I provide a high-voltage commutatorcylinder having a safe creepage path wherein the length of thecommutator cylinder is actually decreased, as compared with existingtypes. Furthermore, my invention may be readily applied to commutatorcylinders of the existing type by a slight modification in the form ofone of the V-rings.

The single figure of the accompanying drawing is a view, partially insection and partially in side elevation, of a portion of a commutatorcylinder embodying my invention.

A plurality of conducting and insulating segments 1 and 2, respectively,are alternately disposed upon V-rings 3 and 1 that are secured togetherby means of throughbolts 5 and serve to maintain the segments 1 and 2 intheir proper relation. The V-ring 3 is shorter than the V-ring 4 and isprovided with a flat annular surface 3 intermediate the ends of thecommutator segments. The segments 1 and 2 thus project beyond the end ofthe V-ring 3, in the form of an annulus, the inner surface of which isof varying diameter. A layer 6 of insulation (preferably mica) isinterposed between the segments 1 and 2 and the V-ring 3 and conforms tothe inner surface of the segments 1 and 2. A ring 7, preferably composed of a hard and durable insulating material, such as bakelite, andof varying diameter is secured to the face 3 of the V-ring 3 by means ofbolts 8 which extend through openings 9 provided in the ring 7. Thewedging action between the conical surfaces of the ring 7 and the micainsulation 6 insures a close fit therebetween. The openings 9 are formedwith a countersunk portion 9 within which plugs 10 of insulatingmaterial are located. The insulating ring 7 is further provided with aninwardly extending annular flange 11 that is spaced from, andsubstantially parallel to, the surface 3 of the V-ring.

From the foregoing, it is apparent that the length of the creepage pathprovided by the insulating ring 7 and its flange 11 is several times Lwhich represents the shortest distance from the end of the conductingsegments 1 to the end of the V-ring. Furthermore, it is apparent that myinvention may be embodied in existing types of commutator cylinders bymerely shortening one V-ring and applying the insulating ring thereto.

While I have shown my invention in its simplest and preferred form, itis not so limited but is capable of various modifications within thescope of the appended claims.

I claim as my invention:

1. In a commutator cylinder, the combination with conducting andinsulating segments, of a, supporting structure therefor, said segmentsprojecting beyond the ends of said supporting structure, and aninsulatin member located within the annulus forme by the projectingportions of said segments, said insulating member having an inwardlyextending flange that is spaced from the remainder of the commutatorstructure and that provides a long creepage path between said segmentsand said supporting structure.

2. In a commutator cylinder, the combi-t nation with conducting andinsulating segments and a supporting V-ring therefor, the said segmentsprojecting beyond the end of said V-ring, of an insulating memberlocated within the annulus formed by the pro jecting portions of saidsegments, sa d insulating member having an inwardly 'pro-' jectingflange to provide a comparatively long creepage path between saidsegments and said 'V-ring.

nation Withfconducting and insulating segments and 'asupporting 'V-rinfgtherefor, the

' said segmentsproject'ing beyond the end of said V ring, of aninsulating"member lo cated withln' the annulus formed by the projectingportions of sald segmentsand ha mg ani'nwardly projecting flange spaced7 from said V ring. a

g 4. In "a con mutator cylinder, the combination with conducting andinsulating'se'gcommutator cylinder, the combiments, of a cylindricalsupporting structure therefor, said segments projecting beyond the endof said-supporting structure, and an insulating member located withinthe annulus formed by the projecting portions of said segments,"saidinsulating member having a tapering portion adapted to exert a we'd inforce a must said se ents and also having aninwardly projecting flangethat 1s spaced from theyrema-mder of the commutator-structure and thatprovides an extended cr'eepage path between said "segments and saidsupporting structure.

" in testimony whereof, I have hereunto subscribed myina-me this22nd dayof Sept,

' RUn'oLF E; HELLMUND.

"Copies (if this patent ma be obtained for five 'cents 'aclij-byajidressiifg tre-commissionermurmurs,

' washington, D. G.

